Battery pack

ABSTRACT

A battery pack includes a plurality of unit batteries arranged side by side in a first direction, each unit battery including a can accommodating an opening including an electrode assembly having a first electrode plate, a second electrode plate, and a separator between the electrode plates, and a cap plate sealing the opening. The plurality of unit batteries may be arranged side by side in the first direction with all the cap plates exposed in the same direction. The battery pack may further include a protection circuit module adjacent to the cap plate with a circuit board extending in the first direction and a protection device coupled to it, wherein each unit battery further includes a first terminal on a first area of the cap plate and a second terminal on a second area of the cap plate, each coupled to the unit battery and the protection circuit module.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.14/077,179, filed Nov. 11, 2013, which claims priority to and thebenefit of U.S. Provisional Application No. 61/844,370, filed on Jul. 9,2013, in the U.S. Patent and Trademark Office, the entire contents ofboth which are incorporated herein by reference.

BACKGROUND

1. Field

The present invention relates to a battery pack.

2. Description of the Related Art

With the development of wireless Internet or communication technology,use of portable computers, which may be operated by using a batterywithout a power supply device, has rapidly increased. In general,portable computers are widely used for work or personal purposes becauseof their compact designs, ease of portability, and high mobility. Aportable computer may include an internal battery pack which allowsextended use of the device in various places without being affected by apower supply device. The internal battery pack in these devices mayinclude unit batteries that may be repeatedly discharged and recharged.

SUMMARY

One or more embodiments of the present invention relate to a batterypack, and in particular, to a structure of a battery pack.

According to an aspect of the present invention, there is provided abattery pack including a plurality of unit batteries arranged side byside in a first direction, each unit battery including a can having anopening, the can accommodating an electrode assembly having a firstelectrode plate, a second electrode plate, and a separator locatedbetween the first electrode plate and the second electrode plate, and acap plate sealing the opening, wherein the plurality of unit batteriesare arranged side by side in the first direction such that the cap plateof each of the unit batteries is exposed in the same direction. Thebattery unit may further include a protection circuit module adjacent tothe cap plate of each of the unit batteries, the protection circuitmodule having a circuit board extending in the first direction and aprotection device coupled to the circuit board, wherein each unitbattery of the plurality of unit batteries further includes a firstterminal on a first area of the cap plate and coupled to the unitbattery and the protection circuit module; and a second terminal on asecond area of the cap plate and coupled to the unit battery and theprotection circuit module.

The circuit board of the battery pack may include at least one terminalhole, wherein an end portion of at least one of the first terminal orthe second terminal is coupled to the terminal hole.

At least one of the first terminal or the second terminal of the batterypack may include a first surface parallel to the cap plate, a secondsurface bent away from the first surface in a direction substantiallyperpendicular to the first surface, and a third surface bent away fromthe second surface in a direction substantially perpendicular to thesecond surface and substantially parallel to the first surface.

The second surface of the first terminal or the second terminal of thebattery pack may be adjacent to a first long side of the cap plate, andthe circuit board may be on a plane adjacent to the second surface.

A height of the protection device of the battery pack may be equal to orless than a distance between the first long side of the cap plate and asecond long side of the cap plate parallel and opposite to the firstlong side.

The circuit board of the battery pack may include at least one terminalhole, wherein the third surface is coupled to the terminal holeelectrically connecting the at least one of the first terminal or thesecond terminal to the circuit board.

Each of the unit batteries of the battery pack may further include anelectrode pin having a first polarity and located on the cap plate,wherein the cap plate has a second polarity that is different from thefirst polarity.

The first terminal of the battery pack may electrically couple theelectrode pin and the protection circuit module, and the second terminalof the battery pack may electrically couple the cap plate and theprotection circuit module.

The battery pack may further include a holder located between the firstterminal and the cap plate, the holder insulating the cap plate from thefirst terminal while exposing the electrode pin.

The first terminal of the battery pack may further include a temperaturecutoff.

Facing surfaces of adjacent unit batteries from among the plurality ofunit batteries of the battery pack may be insulated from each other.

According to another aspect of the present invention, there is provideda battery pack including a plurality of unit batteries, each of the unitbatteries including a can having an opening and including a metalmaterial, an electrode assembly located inside the can and including afirst electrode plate, a second electrode plate, and a separator betweenthe first electrode plate and the second electrode plate, and a capplate sealing the opening of the can; and a protection circuit moduleadjacent to the cap plate of each of the plurality of unit batteries,the protection circuit module including a circuit board and a protectiondevice, wherein each unit battery of the plurality of unit batteriesfurther includes a first terminal electrically coupling the protectioncircuit module and an electrode pin having a first polarity and locatedon the cap plate; and a second terminal electrically coupling theprotective circuit module and the cap plate, the cap plate having asecond polarity that is opposite to the first polarity.

The circuit board of the battery pack may include at least one terminalhole.

A portion of the first terminal and a portion of the second terminal ofthe battery pack may be coupled to the terminal hole.

The battery pack may further include a holder located between the firstterminal and the cap plate, the holder insulating the cap plate from thefirst terminal while exposing the electrode pin.

The first terminal of the battery pack may include a first surfacecoupled to the electrode pin; a second surface bent away from the firstsurface; and a third surface bent away from the second surface andsubstantially parallel to the first surface.

The first surface of the first terminal of the battery pack may includea first portion and a second portion, wherein the first portion and thesecond portion are electrically coupled to each other through atemperature cutoff located between the first portion and the secondportion.

The second terminal of the battery pack may include a first surfacecoupled to the cap plate, a second surface bent away from the firstsurface, and a third surface bent away from the second surface andsubstantially parallel to the first surface.

The battery pack may further include a connection on the cap plate, theconnection piece directly coupled to the second terminal and includingthe same material as a material of the second terminal.

Facing surfaces of adjacent unit batteries from among the plurality ofunit batteries of the battery pack may be insulated from each other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view schematically illustrating a battery packaccording to an embodiment of the present invention.

FIG. 2 is a partially exploded perspective view of the battery packillustrated in FIG. 1.

FIG. 3 is an enlarged perspective view of section III of the batterypack illustrated in FIG. 1.

FIG. 4 is an exploded perspective view illustrating a unit batteryaccording to an embodiment of the present invention.

DETAILED DESCRIPTION

The present invention will now be described more fully with reference tothe accompanying drawings, in which embodiments of the present inventionare shown. It should be understood, however, that there is no intent tolimit embodiments of the present invention to the particular formsdisclosed, but conversely, these embodiments of the present inventionare to cover all modifications, equivalents, and alternatives fallingwithin the spirit and scope of the present invention. In the followingdescription of the present invention, a detailed description of knownfunctions and configurations incorporated herein will be omitted when itmay make the subject matter of the present invention unclear. It will beunderstood that, although the terms “first”, “second”, etc. may be usedherein to describe various elements, these elements should not belimited by these terms. These terms are only used to distinguish oneelement from another. The terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting of the embodiments of the invention. As used herein, thesingular forms “a”, “an” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. It willbe further understood that the terms “comprises”, “comprising,”,“includes” and/or “including”, when used herein, specify the presence ofstated features, integers, steps, operations, elements, parts, orcombinations thereof, but do not preclude the presence or addition ofone or more other features, integers, steps, operations, elements,parts, or combinations thereof. A function mark “I” may be used to mean“and” or “or” according to the context in which it is used.

Like numerals denote like elements throughout. It will also beunderstood that when a layer, film, region, or plate is referred to asbeing “on” another layer, film, region, or plate, it can be directly onthe other layer, film, region, or plate, or intervening layers, films,regions, or plates may also be present therebetween.

FIG. 1 is a perspective view schematically illustrating a battery packaccording to an embodiment of the present invention. FIG. 2 is apartically exploded perspective view of the battery pack illustrated inFIG. 1. FIG. 3 is an enlarged perspective view of section III of thebattery pack illustrated in FIG. 1.

Referring to the embodiments illustrated in FIGS. 1 and 2, the batterypack includes a plurality of unit batteries 1 and a protection circuitmodule 60. Each of the unit batteries 1 in these embodiments includesfirst and second terminals 30 and 40, and is directly electricallyconnected to the protection circuit module 60.

Each of the unit batteries 1 in these embodiments is a rechargeablesecondary battery and may be, for example, a lithium-ion battery. In theembodiments illustrated in FIGS. 1 and 2, each of the unit batteries 1is manufactured to have a prismatic shape, for example, in oneembodiment, each unit battery 1 has a substantially hexahedral shape.Each of the unit batteries 1 in these embodiments includes a can 10 (asshown in FIG. 4) and a cap plate 20 (as shown in FIG. 4) sealing a sidesurface of the can 10. The unit batteries 1 may be arranged side by sidein a first direction D1 such that the cap plates 20 are exposed in thesame direction, as illustrated in FIG. 1. For example, as shown in theembodiment illustrated in FIG. 1, four unit batteries 1 may be arrangedside by side in the first direction D1 such that the cap plates 20 areexposed in a second direction D2, and two unit batteries 1 may bearranged side by side in the first direction D1 such that their capplates 20 are exposed in an opposite second direction −D2 opposite tothe second direction D2.

Although in the embodiment illustrated in FIG. 1 four unit batteries 1are aligned with their cap plates 20 exposed in the second direction D2,and two unit batteries 1 are aligned with their cap plates 20 exposed inthe opposite second direction −D2, to face each other, the number andarrangement of the unit batteries 1 are not limited thereto.Alternatively, in other embodiments, two or more unit batteries 1 may bearranged side by side in the first direction D1, for example.

In the embodiments illustrated in FIGS. 1 and 2, the first terminal 30and the second terminal 40 are located on a side surface of each of theunit batteries 1, i.e., on the cap plate 20. In these embodiments,either one of the first or second terminals 30 or 40 may be a negativeelectrode of its respective unit battery 1 with the other terminal 30 or40 as a positive electrode of the unit battery 1. FIG. 1 will be furtherdescribed with the assumption that the first terminal 30 is a negativeelectrode and the second terminal 40 is a positive electrode.

In the embodiment illustrated in FIGS. 1 and 2, the first terminal 30 islocated on the cap plate 20 with an end portion of the first terminal 30positioned away from the cap plate 20 extending toward the protectioncircuit module 60. In this embodiment, the end portion of the firstterminal 30 extending toward the protection circuit module 60 is bent.

In the embodiment illustrated in FIGS. 1 and 2, the second terminal 40is located on the cap plate 20 with an end portion of the secondterminal 40 positioned away from the cap plate 20 extending toward theprotection circuit module 60. In this embodiment, the end portion of thesecond terminal 40 extending toward the protection circuit module 60 isbent.

The bent end portions of the first and second terminals 30 and 40 in theembodiments illustrated in FIGS. 1 and 2 are inserted into terminalholes 61 h in the protection circuit module 60. Each of the unitbatteries 1 in these embodiments is electrically connected to theprotection circuit module 60 when the bent end portions of the first andsecond terminals 30 and 40 are inserted into the terminal holes 61 h.

The protection circuit module 60 may be located adjacent to the capplates 20 of the unit batteries 1 and may be electrically connected tothe unit batteries 1 to control discharging and recharging of the unitbatteries 1. In these embodiments, the protection circuit module 60 may,thus, prevent overheating and reduce the risk of explosion caused by anover-recharge, an over-discharge, or an over-current. The protectioncircuit module 60 in these embodiments includes a circuit board 61 and aplurality of protection devices 62 coupled to the circuit board 61.

in the embodiments illustrated in FIGS. 1 and 2, the circuit board 61includes at least one terminal hole 61 h. The terminal hole 61 h may belocated at an edge of the circuit board 61, and each of the unitbatteries 1 may be directly connected to the protection circuit module60 at the terminal hole 61 h when the first and second terminals 30 and40 are inserted into the terminal holes 61 h.

As shown in the embodiment illustrated in FIG. 3, the bent end portionsof the first and second terminals 30 and 40 may be inserted into theterminal holes 61 h in the circuit board 61, and, in an embodiment, theterminal holes 61 h may have slit shapes extending along the firstdirection D1. In this embodiment, the bent end portion of the firstterminal 30 and the bent end portion of the second terminal 40 are eachinserted into their respective terminal holes 61 h and soldered.

Since each of the unit batteries 1 in the embodiments illustrated inFIGS. 1-3 is directly connected to the protection circuit module 60through the first and second terminals 30 and 40 provided on the capplate 20, the recharging and discharging of each of the unit batteries 1may be controlled by the protection circuit module 60, and each of theunit batteries 1 may be connected in parallel and/or series throughwires on the protection circuit module 60. In this embodiment, becauseeach of the unit batteries 1 is directly connected to the protectioncircuit module 60, an intermediate member for connecting the pluralityof unit batteries 1 in parallel and/or series is not necessary.Accordingly, in this embodiment, an additional space to accommodate theintermediate member is not necessary, allowing for a reduction in thetotal number of parts necessary for manufacturing the battery packaccording to the embodiments of the present invention.

In the embodiments illustrated in FIGS. 1-3, the circuit board 61 islocated adjacent to the cap plate 20, and extends along the firstdirection D1. In this embodiment, the circuit board 61 may be located ona plane adjacent to second surfaces 32 and 42 (as shown in FIG. 4) ofthe first and second terminals 30 and 40, respectively, which may belocated, for example, on substantially the same plane as a bottomsurface of each of the unit batteries 1. In embodiments where thecircuit board 61 is located in the manner described above, a space maybe formed between a top surface of the circuit board 61 and the capplate 20, and the plurality of protection devices 62 may be positionedin this space. A height of each of the protection devices 62 may beequal to or less than a thickness of each of the unit batteries 1,measured as a distance between a first long side l1 and a second longside l2 opposite the first long side l1 of the cap plate 20 (as shown inFIG. 4). In this embodiment, the protection devices 62 may beeffectively coupled to the circuit 61 without increasing a thickness ora width of the battery pack.

The protection device 62 in these embodiments may include a safetyelement, for example a passive element such as a resistor or acondenser, and an active element such as a field-effect transistor(FET), or integrated circuits. The protection circuit module 60 in theseembodiments may further include a connector 63 for supplying power to anexternal electronic device. The connector 63 may be located at a side ofthe protection circuit module 60.

A structure of each of the unit batteries 1 including the first andsecond terminals 30 and 40 will be explained in further detail belowwith reference to the embodiments illustrated in FIG. 4.

FIG. 4 is an exploded perspective view illustrating a unit batteryaccording to an embodiment of the present invention.

Referring to the embodiment illustrated in FIG. 4, the unit battery 1includes the can 10, including an electrode assembly received through anopening in the can 10, the cap plate 20, sealing the opening of the can10, and the first and second terminals 30 and 40.

In the embodiment illustrated in FIG. 4, the can 10 has a substantiallyhexahedral shape with an opening at one side, and may be formed of ametal material, increasing its strength. For example, in one embodiment,the can 10 may be formed of aluminum or an aluminum alloy. After theelectrode assembly is inserted into the can 10, the opening may besealed by the cap plate 20. The cap plate 20, like the can 10, may beformed of a metal material such as aluminum or an aluminum alloy. Pointsof contact between the cap plate 20 and the can 10, in some embodiments,may be coupled by laser welding to maintain a sealing engagement.

In some embodiments, each of the can 10 and the cap plate 20 is formedof a metal material, however no insulating films or labels surround anouter circumferential surface of the can 10. Accordingly, in theseembodiments, when the unit batteries 1 are arranged side by side asshown in FIG. 1, since short-circuit may occur between adjacent unitbatteries 1 having no, facing surfaces of the adjacent unit batteries 1,having no insulation films or labels surrounding the outer surface ofthe can 10, may require insulation from each other to preventshort-circuiting. For example, in some embodiments, both side surfacesof the can 10 which are exposed in the first direction D1 along thesecond direction D2 may be insulated by using an insulating tape I.Alternatively, in other embodiments, both side surfaces of the can 10may be insulated by placing an insulating barrier between adjacent unitbatteries 1.

In the embodiments shown in FIGS. 1-4, the electrode assembly mayinclude a first electrode plate and a second electrode plate each coatedwith an electrode active material, and a separator located between thefirst and second electrode plates. The electrode assembly may bemanufactured by sequentially stacking the first electrode plate, theseparator, and the second electrode plate, and winding the firstelectrode plate, the separator, and the second electrode plate in ajelly roll shape.

Although the electrode assembly described above may have a jelly rollshape, the embodiments of the present invention are not limited thereto.Alternatively, in some embodiments, for example, the electrode assemblymay have a stacked structure in which the first electrode plate, theseparator, and the second electrode plate are sequentially stacked.

In the embodiments shown in FIG. 4, an electrode pin 21 is formed on thecap plate 20. In these embodiments, the first electrode plate of theelectrode assembly is electrically connected to the electrode pin 21,and the second electrode plate is electrically connected to the capplate 20. Since the first electrode plate and the second electrode platehave different polarities, the electrode pin 21 and the cap plate 20 inthese embodiments have different polarities. For example, in oneembodiment, the electrode pin 21 may have the polarity of a negativeelectrode, and the cap plate 20 may have the polarity of a positiveelectrode. In this embodiment, a gasket 23 may be positioned between theelectrode pin 21 and the cap plate 20 in order to prevent ashort-circuit between the electrode pin 21 and the cap plate 20. Thegasket 23 in this embodiment may be formed of an insulating materialpreventing a short-circuit between the electrode pin 21 and the capplate 20.

In the embodiments shown in FIG. 4, the first terminal 30 and the secondterminal 40 are located on the cap plate 20. In these embodiments, thefirst terminal 30 is located on a portion (first area) of the cap plate20, and the second terminal 40 is located on a different portion (secondarea) of the cap plate 20. In an embodiment, the first terminal 30 maybe positioned on the first area of the cap plate 20 to be electricallyconnected to the electrode pin 21, and the second terminal 40 may bepositioned on the second area of the cap plate 20 to be electricallyconnected to the cap plate 20. In this embodiment, a connection piece 22may be coupled to the cap plate 20 in order to improve a welding surfacebetween the cap plate 20 and the second terminal 40, which may each beformed of different materials. The connection piece 22 may be formed ofthe same material as the second terminal 40. For example, in anembodiment, both the connection piece 22 and the first and secondterminals 30 and 40 may nickel.

In the embodiments shown in FIG. 4, the first terminal 30 may include afirst surface 31 parallel to the cap plate 20, the second surface 32bent away from the first surface 31, and a third surface 33 bent awayfrom the second surface 32 and substantially parallel to the firstsurface 31.

In the embodiments shown in FIG. 4, the first terminal 30 may include atemperature cutoff (TCO) 35. In this embodiment, the first surface 31 ofthe first terminal 30 may be divided into a first portion 31 a and asecond portion 31 b. The first portion 31 a and the second portion 31 bmay be located on the same plane, and the TCO 35 may be electricallyconnected to the first surface 31 of the first terminal 30 between thefirst portion 31 a and the second portion 31 b. For example, in anembodiment, a first end 35 a of the TCO 35 may be connected to an end ofthe first portion 31 a of the first surface 31, and a second end 35 b ofthe TCO 35 may be connected to an end of the second portion 31 b of thefirst surface 31, as shown in FIG. 4.

Since the first terminal 30 shown in the embodiments illustrated inFIGS. 1-4 is electrically connected to the electrode pin 21, the firstterminal 30 in these embodiments has a negative electrode polarity. Incontrast, since the cap plate 20 shown in the embodiments illustrated inFIGS. 1-4 has a positive electrode polarity, a short-circuit may easilyoccur between the cap plate 20 and the first terminal 30 that is locatedon the cap plate 20. Accordingly, in these embodiments, a holder 50 maybe positioned between the first terminal 30 and the cap plate 20 toelectrically insulate between the first terminal 30 and the cap plate 20(as shown in FIG. 4).

The holder 50 in the embodiments illustrated in FIG. 4 is directlylocated on the cap plate 20, and includes a first opening OP1 throughwhich the first surface 31 of the first terminal 30 is electricallyconnected to the electrode pin 21. The holder 50 may further include asecond opening OP2 located on a surface of the holder 50 facing the TCO35, allowing the TCO 35 coupled to the first terminal 30 to effectivelyrespond to a temperature of the unit battery 1.

The holder 50 shown in the embodiments of FIG. 4 may include aprotrusion 51 for coupling the holder 50 with the first terminal 30. Inan embodiment where the first terminal 30 is mounted to the holder 50,the first portion 31 a of the first surface 31 of the first terminal 30may be welded to the electrode pin 21, and the second portion 31 b ofthe first surface 31 of the first terminal 30 may be coupled to theprotrusion 51. A hole 30 h may be formed in the second portion 31 b ofthe first surface 31. In this embodiment, when the protrusion 51 isinserted into the hole 30 h and heat is applied to a portion of an upperend of the protrusion 51, the portion of the upper end of the protrusion51 may melt, coupling the first terminal 30 to the holder 50. A tape 55coupled to the holder 50 may be further attached to the unit battery 1,as shown in the embodiments illustrated in FIGS. 3 and 4, in order toprevent the first terminal 30 that is coupled to the holder 50 andwelded to the electrode pin 21 from separating from the unit battery 1.

In the embodiments illustrated in FIG. 4, the second surface 32 of thefirst terminal 30 may be bent in a direction substantially perpendicularto the first surface 31, and the third surface 33 may be bent in adirection substantially perpendicular to the second surface 32. In theseembodiments, the second surface 32 is adjacent to the first long side £1of the cap plate 20. The third surface 33 of the first terminal 30 inthese embodiments is inserted as an end portion of the first terminal 30into the terminal hole 61 h of the protection circuit module 60, asdescribed above with reference to FIGS. 1 through 3.

In the embodiments illustrated in FIG. 4, the second terminal 40 mayinclude a first surface 41 parallel to the cap plate 20, a secondsurface 42 bent away from the first surface 41, and a third surface 43bent away from the second surface 42 and substantially parallel to thefirst surface 41. The second surface 42 of the second terminal 40 may bebent in a direction substantially perpendicular to the first surface 41,and the third surface 43 may be bent in a direction substantiallyperpendicular to the second surface 42. The third surface 43 of thesecond terminal 40 in these embodiments is inserted as an end portion ofthe second terminal 40 into the terminal hole 61 h of the protectioncircuit module 60, as described above with reference to FIGS. 1 through3.

According to the one or more embodiments of the present invention, sinceeach of unit batteries 1 is directly connected to a protection circuitmodule 60 through first and second terminals 30 and 40, the unitbatteries 1 may be controlled by the protection circuit module 60 to bedischarged and recharged, and may be connected in parallel and/or seriesthrough wires on the protection circuit module 60. Accordingly, anintermediate member for connecting the plurality of unit batteries 1 inparallel and/or series is not necessary, and an additional space for theintermediate member is also not necessary, making it possible to reducethe total number of parts for manufacturing a battery pack.

While the present invention has been particularly shown and describedwith reference to embodiments thereof, the embodiments are provided forthe purposes of illustration, and it should be understood by those ofordinary skill in the art that various modifications and equivalentother embodiments may be made from the present invention.

Description of Reference Numerals

-   1: unit battery-   10: can-   20: cap plate-   21: electrode pin-   22: connection piece-   23: gasket-   30: first terminal-   30 h: hole formed in the second portion of the first surface-   31: first surface of the first terminal-   31 a: first portion of the first surface of the first terminal-   31 b: second portion of the first surface of the first terminal-   32: second surface of the first terminal-   33: third surface of the first terminal (end portion of the first    terminal)-   35: temperature cutoff (TCO)-   35 a: first end of the TCO-   35 b: second end of the TCO-   40: second terminal-   41: first surface of the second terminal-   42: second surface of the second terminal-   43: third surface of the second terminal (end portion of the second    terminal)-   50: holder-   51: protrusion-   55: a tape fixed to the holder-   OP1: first opening on the holder-   OP2: second opening on the holder-   60: protection circuit module-   61: circuit board-   61 h: terminal hole-   62: protection device-   63: connector-   I: insulating tape

What is claimed is:
 1. A battery pack comprising: a plurality of unitbatteries arranged side by side in a first direction, each unit batterycomprising: a can having an opening, the can accommodating an electrodeassembly comprising a first electrode plate, a second electrode plate,and a separator located between the first electrode plate and the secondelectrode plate, and a cap plate sealing the opening, wherein theplurality of unit batteries are arranged side by side in the firstdirection such that the cap plate of each of the unit batteries isexposed in the same direction; and a protection circuit module adjacentto the cap plate of each of the unit batteries, the protection circuitmodule comprising a circuit board extending in the first direction and aprotection device coupled to the circuit board, wherein each unitbattery of the plurality of unit batteries further comprises a firstterminal on a first area of the cap plate and coupled to the unitbattery and the protection circuit module; and a second terminal on asecond area of the cap plate and coupled to the unit battery and theprotection circuit module.
 2. The battery pack of claim 1, wherein thecircuit board comprises at least one terminal hole, and wherein an endportion of at least one of the first terminal or the second terminal iscoupled to the terminal hole.
 3. The battery pack of claim 1, wherein atleast one of the first terminal or the second terminal comprises: afirst surface parallel to the cap plate; a second surface bent away fromthe first surface in a direction substantially perpendicular to thefirst surface; and a third surface bent away from the second surface ina direction substantially perpendicular to the second surface andsubstantially parallel to the first surface.
 4. The battery pack ofclaim 3, wherein the second surface is adjacent to a first long side ofthe cap plate, and the circuit board is on a plane adjacent to thesecond surface.
 5. The battery pack of claim 4, wherein a height of theprotection device is equal to or less than a distance between the firstlong side of the cap plate and a second long side of the cap plateparallel and opposite to the first long side.
 6. The battery pack ofclaim 3, wherein the circuit board comprises at least one terminal hole,and wherein the third surface is coupled to the terminal holeelectrically connecting the at least one of the first terminal or thesecond terminal to the circuit board.
 7. The battery pack of claim 1,wherein each of the unit batteries further comprises an electrode pinhaving a first polarity and located on the cap plate, and wherein thecap plate has a second polarity that is different from the firstpolarity.
 8. The battery pack of claim 7, wherein the first terminalelectrically couples the electrode pin and the protection circuitmodule, and the second terminal electrically couples the cap plate andthe protection circuit module.
 9. The battery pack of claim 7, furthercomprising a holder located between the first terminal and the capplate, the holder insulating the cap plate from the first terminal whileexposing the electrode pin.
 10. The battery pack of claim 1, wherein thefirst terminal further comprises a temperature cutoff.
 11. The batterypack of claim 1, wherein facing surfaces of adjacent unit batteries fromamong the plurality of unit batteries are insulated from each other. 12.A battery pack comprising: a plurality of unit batteries, each of theunit batteries comprising a can having an opening and comprising a metalmaterial, an electrode assembly located inside the can and comprising afirst electrode plate, a second electrode plate, and a separator betweenthe first electrode plate and the second electrode plate, and a capplate sealing the opening of the can; and a protection circuit moduleadjacent to the cap plate of each of the plurality of unit batteries,the protection circuit module comprising a circuit board and aprotection device, wherein each unit battery of the plurality of unitbatteries further comprises a first terminal electrically coupling theprotection circuit module and an electrode pin having a first polarityand located on the cap plate; and a second terminal electricallycoupling the protective circuit module and the cap plate, the cap platehaving a second polarity that is opposite to the first polarity.
 13. Thebattery pack of claim 12, wherein the circuit board comprises at leastone terminal hole.
 14. The battery pack of claim 13, wherein a portionof the first terminal and a portion of the second terminal are coupledto the terminal hole.
 15. The battery pack of claim 12, furthercomprising a holder located between the first terminal and the capplate, the holder insulating the cap plate from the first terminal whileexposing the electrode pin.
 16. The battery pack of claim 12, whereinthe first terminal comprises: a first surface coupled to the electrodepin; a second surface bent away from the first surface; and a thirdsurface bent away from the second surface and substantially parallel tothe first surface.
 17. The battery pack of claim 16, wherein the firstsurface comprises a first portion and a second portion, and wherein thefirst portion and the second portion are electrically coupled to eachother through a temperature cutoff located between the first portion andthe second portion.
 18. The battery pack of claim 12, wherein the secondterminal comprises: a first surface coupled to the cap plate; a secondsurface bent away from the first surface; and a third surface bent awayfrom the second surface and substantially parallel to the first surface.19. The battery pack of claim 12, further comprising a connection pieceon the cap plate, the connection piece directly coupled to the secondterminal, and comprising the same material as a material of the secondterminal.
 20. The battery pack of claim 12, wherein facing surfaces ofadjacent unit batteries from among the plurality of unit batteries areinsulated from each other.